作业：
[total_score, user => [username, realname], scores[]]
$standings = [];
foreach ($usernames as $username) {
$user = queryUser($username);
$row = ['total_score' => 0];
$scores = [];
$row['user'] = [
'username' => $user['username'],
'realname' => $user['realname'],
];
$cond = "submitter = '{$user['username']}' AND unix_timestamp(submit_time) <= " . $submission_end_time->getTimestamp();
$cond_problem = "problem_id IN (".implode(',', $problem_ids).")";
$query = DB::query("SELECT MAX(id) as id, problem_id, MAX(score) as score FROM submissions WHERE (problem_id, score) IN (SELECT problem_id, MAX(score) FROM submissions WHERE $cond AND $cond_problem GROUP BY problem_id) AND $cond GROUP BY problem_id");
while ($_row = DB::fetch($query)) {
$scores[$_row['problem_id']] = [
'submission_id' => $_row['id'],
'score' => $_row['score'],
];
}
foreach ($problem_ids as $problem_id) {
if ($scores[$problem_id]) {
$row['scores'][] = [
'submission_id' => $scores[$problem_id]['submission_id'],
'score' => intval($scores[$problem_id]['score']),
];
$row['total_score'] += $scores[$problem_id]['score'];
} else {
$row['scores'][] = null;
}
}
$standings[] = $row;
}
usort($standings, function($lhs, $rhs) {
if ($lhs['total_score'] != $rhs['total_score']) {
return $rhs['total_score'] - $lhs['total_score'];
}
return strcmp($lhs['user']['username'], $rhs['user']['username']);
});
?>